1. Field of the Invention
The present invention relates to a method and apparatus for monitoring a milking process. More particularly the present invention relates to monitoring a milking process obtaining an indication of volume of displaced air within a teatcup.
2. Description of the Related Art
In any milking system, it is important to ensure that teatcups are properly connected to the teats of animals being milked. Improper connection may result in inefficient milking—if any milk at all may be extracted—and potentially cause damage to the udder. If a teatcup becomes completely disconnected, there is a risk that extraneous material within the milking environment will be sucked into the milk delivery system, which is highly undesirable.
The ability to detect this is especially important in an automated milking system, such as those controlled by a robot, where operators are not always present to observe an improper connection and readjust the teatcup.
Currently, sound and pressure measurements within the milking line are commonly used to determine whether the teatcup is properly connected. Document EP-0953829A1 which is hereby incorporated by reference in its entirety, provides an example of one such method based on the measurement of sound within the milking line and comparison of these measurements with predetermined reference values to determine whether present conditions within the line indicate that the teatcup is correctly connected to the teat.
Such methods suffer limitations due to the nature of the environment within the milking line. In particular, the passage of liquid within the line creates significant levels of interference which makes obtaining consistent and accurate measurements difficult. Connection of the milking line to other elements within the milking plant also introduces other sources of noise. As a result such techniques have low sensitivity as to the quality of the connection.
Furthermore, such methods require placement of sensors within the milking line between the teatcups and milk receiver. The environment surrounding the teatcups is harsh, for example due to exposure to liquid (including cleaning chemicals), impact, and variation in temperature. Positioning of the sensor at this point is also not conducive to the generally desirable objective of minimising bulk and weight to the milking implement. Also, being associated with the milking line the apparatus is subject to greater scrutiny with regard to health standards.